A chromatogram is a graph of the response in chromatography that is measured by a detector at the end of the column as a function of the time or volume of mobile phase that is needed for elution.
a) The void time is the time required for a totally nonbinding substance to travel through the column during chromatography.
b) The void volume is the volume of mobile phase that it takes to elute a totally no nretained substance from a chromatographic system.
c) The retention time is the average time required for a given retained substance to pass through a chromatographic system.
d) The retention volume is the average volume of mobile phase required to pass a given retained substance through a chromatographic system.